PROJECT SUMMARY/ ABSTRACT Diabetes is a significant U.S. public health burden?one that is not equally distributed through the population. In the U.S., almost 30 million adults have diabetes mellitus (DM), and an additional 84 million are considered pre- diabetic and at risk for developing the condition. Disease onset is strongly predicted by race/ethnicity, with non- Hispanic blacks, Hispanics, and Asian-Americans reporting higher incidence and prevalence rates than non- Hispanic whites. Similar disparate patterns are observed for DM-related complications and greater disease severity, including excess mortality and reduced physical and cognitive functional status. Although a number of factors have been identified as possible contributors to DM-related health disparities (including socioeconomic, environmental, psychosocial, and lifestyle/behavioral factors), race/ethnicity continues to demonstrate predictive power that cannot be fully explained by other factors. A growing body of evidence suggests a positive relationship between work hour patterns and DM onset, particularly among work groups who may experience less desirable working conditions and arrangements. However, little is known about the sociodemographic distribution of work hours (WH) or DM-related occupational risks. We will address these limitations by describing ? for the first time ? WH patterns in a representative sample of U.S. workers by race/ethnicity (Aim 1) and assessing ? for the first time ? the effects of longitudinal, time-varying WH patterns on incident DM by race/ethnicity (Aim 2). Then ? for the first time ? we will estimate the influence of WH and race/ethnicity on DM progression and general health decline (Aim 3). These aims will be executed in a data set constructed by merging a nationally representative panel study (Panel Study of Income Dynamics, or PSID) with job-characteristics data sponsored by the U.S. Department of Labor (U.S. Occupational Information Network, or O*NET) across 30 years to yield one of the most comprehensive data sets to date for the examination of the influence of work-related factors on DM onset and progression among minority populations. The proposed project supports the National Institute on Minority Health and Health Disparities? focus on social and behavioral research to better understand the risk and protective factors related to the development of health conditions in health disparity populations. Findings from this cost-effective, innovative study will broaden our scientific understanding of the influence of WH on DM development and progression in vulnerable populations and could have substantial Research to Practice (r2p) implications across multiple programmatic and policy arenas, including healthcare, education, and workplace wellness. Workplace practices, including long WH, can be addressed (at least partially) through workplace and policy interventions. Policies to encourage healthier work environments ? especially for jobs likely to be held by the most disadvantaged demographic groups ? should be proposed as part of a comprehensive strategy to reduce and, ultimately, eliminate the extent of these health inequalities.